Test with debug builds.

Numeric/RegisterSizes.hpp

@@ -18,7 +18,7 @@
 namespace CPU {
 
 /// Provides access to all intermediate parts of a larger int.
-template <typename Full, typename Half> union alignas(Full) alignas(Half) RegisterPair {
+template <typename Full, typename Half> union alignas(alignof(Full)) RegisterPair {
 	RegisterPair(Full v) : full(v) {}
 	RegisterPair() {}
 

OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj

@@ -186,6 +186,7 @@
 		4B0F1C242605996900B85C66 /* ZXSpectrumTAP.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B0F1C212605996900B85C66 /* ZXSpectrumTAP.cpp */; };
 		4B0F94FE208C1A1600FE41D9 /* NIB.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B0F94FC208C1A1600FE41D9 /* NIB.cpp */; };
 		4B0F94FF208C1A1600FE41D9 /* NIB.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B0F94FC208C1A1600FE41D9 /* NIB.cpp */; };
+		4B11D49028D8F60300070EA7 /* Z80JSMooTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4B11D48F28D8F60300070EA7 /* Z80JSMooTests.mm */; };
 		4B121F9B1E06293F00BFDA12 /* PCMSegmentEventSourceTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4B121F9A1E06293F00BFDA12 /* PCMSegmentEventSourceTests.mm */; };
 		4B12C0ED1FCFA98D005BFD93 /* Keyboard.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B12C0EB1FCFA98D005BFD93 /* Keyboard.cpp */; };
 		4B12C0EE1FCFAD1A005BFD93 /* Keyboard.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B12C0EB1FCFA98D005BFD93 /* Keyboard.cpp */; };
@@ -247,6 +248,7 @@
 		4B30512D1D989E2200B4FED8 /* Drive.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B30512B1D989E2200B4FED8 /* Drive.cpp */; };
 		4B3051301D98ACC600B4FED8 /* Plus3.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B30512E1D98ACC600B4FED8 /* Plus3.cpp */; };
 		4B322E041F5A2E3C004EB04C /* Z80Base.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B322E031F5A2E3C004EB04C /* Z80Base.cpp */; };
+		4B32DBD128E3DB3200F4A16A /* MacintoshVolume.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B4C81C928B56CF800F84AE9 /* MacintoshVolume.cpp */; };
 		4B37EE821D7345A6006A09A4 /* BinaryDump.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B37EE801D7345A6006A09A4 /* BinaryDump.cpp */; };
 		4B38F3481F2EC11D00D9235D /* AmstradCPC.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B38F3461F2EC11D00D9235D /* AmstradCPC.cpp */; };
 		4B3BA0C31D318AEC005DD7A7 /* C1540Tests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B3BA0C21D318AEB005DD7A7 /* C1540Tests.swift */; };
@@ -1298,6 +1300,7 @@
 		4B0F94FC208C1A1600FE41D9 /* NIB.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = NIB.cpp; sourceTree = "<group>"; };
 		4B0F94FD208C1A1600FE41D9 /* NIB.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = NIB.hpp; sourceTree = "<group>"; };
 		4B0F9500208C42A300FE41D9 /* Target.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; name = Target.hpp; path = AppleII/Target.hpp; sourceTree = "<group>"; };
+		4B11D48F28D8F60300070EA7 /* Z80JSMooTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = Z80JSMooTests.mm; sourceTree = "<group>"; };
 		4B121F9A1E06293F00BFDA12 /* PCMSegmentEventSourceTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = PCMSegmentEventSourceTests.mm; sourceTree = "<group>"; };
 		4B12C0EB1FCFA98D005BFD93 /* Keyboard.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = Keyboard.cpp; sourceTree = "<group>"; };
 		4B12C0EC1FCFA98D005BFD93 /* Keyboard.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Keyboard.hpp; sourceTree = "<group>"; };
@@ -4492,6 +4495,7 @@
 				4B1D08051E0F7A1100763741 /* TimeTests.mm */,
 				4BEE4BD325A26E2B00011BD2 /* x86DecoderTests.mm */,
 				4BDA8234261E8E000021AA19 /* Z80ContentionTests.mm */,
+				4B11D48F28D8F60300070EA7 /* Z80JSMooTests.mm */,
 				4BB73EB81B587A5100552FC2 /* Info.plist */,
 				4BC9E1ED1D23449A003FCEE4 /* 6502InterruptTests.swift */,
 				4B92EAC91B7C112B00246143 /* 6502TimingTests.swift */,
@@ -6260,6 +6264,7 @@
 				4B778F4223A5F1A70000D260 /* MemoryFuzzer.cpp in Sources */,
 				4B778F0123A5EBA00000D260 /* MacintoshIMG.cpp in Sources */,
 				4B7752AD28217E770073E2C5 /* AmigaADF.cpp in Sources */,
+				4B32DBD128E3DB3200F4A16A /* MacintoshVolume.cpp in Sources */,
 				4BFF1D3D2235C3C100838EA1 /* EmuTOSTests.mm in Sources */,
 				4B3F76B925A1635300178AEC /* PowerPCDecoderTests.mm in Sources */,
 				4B778F0A23A5EC150000D260 /* TapePRG.cpp in Sources */,
@@ -6293,6 +6298,7 @@
 				4B924E991E74D22700B76AF1 /* AtariStaticAnalyserTests.mm in Sources */,
 				4B90467622C6FD6E000E2074 /* 68000ArithmeticTests.mm in Sources */,
 				4B778F3423A5F1040000D260 /* DirectAccessDevice.cpp in Sources */,
+				4B11D49028D8F60300070EA7 /* Z80JSMooTests.mm in Sources */,
 				4B7BC7F51F58F27800D1B1B4 /* 6502AllRAM.cpp in Sources */,
 				4BC5C3E022C994CD00795658 /* 68000MoveTests.mm in Sources */,
 				4B778F5923A5F2D00000D260 /* Z80.cpp in Sources */,

OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme

@@ -27,6 +27,8 @@
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       shouldUseLaunchSchemeArgsEnv = "YES"
+      enableASanStackUseAfterReturn = "YES"
+      enableUBSanitizer = "YES"
       disableMainThreadChecker = "YES"
       codeCoverageEnabled = "YES">
       <MacroExpansion>

OSBindings/Mac/Clock SignalTests/Z80ContentionTests.mm

@@ -85,7 +85,7 @@ struct CapturingZ80: public CPU::Z80::BusHandler {
 		//
 		// Log the plain bus activity.
 		//
-		const uint8_t *const bus_state = cycle.bus_state();
+		const auto bus_state = cycle.bus_state<CPU::Z80::PartialMachineCycle::SampleType::Period>();
 		for(int c = 0; c < cycle.length.as<int>(); c++) {
 			bus_records_.emplace_back();
 

OSBindings/Mac/Clock SignalTests/Z80JSMooTests.mm

@@ -0,0 +1,381 @@
+//
+//  Z80JSMooTests.cpp
+//  Clock SignalTests
+//
+//  Created by Thomas Harte on 19/9/2022.
+//  Copyright © 2022 Thomas Harte. All rights reserved.
+//
+
+#import <XCTest/XCTest.h>
+
+#include <optional>
+#include "../../../Processors/Z80/Z80.hpp"
+
+namespace {
+
+// Tests are not duplicated into this repository due to their size;
+// put them somewhere on your local system and provide the path here.
+constexpr const char *TestPath = "/Users/thomasharte/Projects/jsmoo/misc/tests/GeneratedTests/z80/v1";
+
+#define MapFields()	\
+		Map(A, @"a");	Map(Flags, @"f");	Map(AFDash, @"af_");	\
+		Map(B, @"b");	Map(C, @"c");		Map(BCDash, @"bc_");	\
+		Map(D, @"d");	Map(E, @"e");		Map(DEDash, @"de_");	\
+		Map(H, @"h");	Map(L, @"l");		Map(HLDash, @"hl_");	\
+																	\
+		Map(IX, @"ix");		Map(IY, @"iy");							\
+		Map(IFF1, @"iff1");	Map(IFF2, @"iff2");						\
+		Map(IM, @"im");												\
+		Map(I, @"i");		Map(R, @"r");							\
+																	\
+		Map(ProgramCounter, @"pc");									\
+		Map(StackPointer, @"sp");									\
+		Map(MemPtr, @"wz");											\
+		Map(DidChangeFlags, @"q");
+
+		/*
+			Not used:
+
+				EI (duplicative of IFF1?)
+				p
+		*/
+
+struct CapturingZ80: public CPU::Z80::BusHandler {
+
+	CapturingZ80(NSDictionary *state, NSArray *port_activity) : z80_(*this) {
+		z80_.reset_power_on();
+
+		// Set registers.
+#define Map(register, name)	z80_.set_value_of(CPU::Z80::Register::register, [state[name] intValue])
+		MapFields();
+#undef Map
+
+		// Populate RAM.
+		for(NSArray *byte in state[@"ram"]) {
+			const int address = [byte[0] intValue] & 0xffff;
+			const int value = [byte[1] intValue];
+			ram_[address] = value;
+		}
+
+		// Capture expected port activity.
+		for(NSArray *item in port_activity) {
+			expected_port_accesses_.emplace_back([item[0] intValue], [item[1] intValue], [item[2] isEqualToString:@"r"]);
+		}
+		next_port_ = expected_port_accesses_.begin();
+	}
+
+	bool compare_state(NSDictionary *state) {
+		bool failed = false;
+
+		// Compare registers.
+		//
+		// TEMPORARILY: DON'T COMPARE DidChangeFlags OR MemPtr.
+#define Map(register, name)	\
+	if(	\
+		CPU::Z80::Register::register != CPU::Z80::Register::DidChangeFlags &&	\
+		CPU::Z80::Register::register != CPU::Z80::Register::MemPtr &&	\
+		z80_.value_of(CPU::Z80::Register::register) != [state[name] intValue]) {	\
+		NSLog(@"Register %s should be %02x; is %02x", #register, [state[name] intValue], z80_.value_of(CPU::Z80::Register::register));	\
+		failed = true;	\
+	}
+
+		MapFields()
+
+#undef Map
+
+		// Compare RAM.
+		for(NSArray *byte in state[@"ram"]) {
+			const int address = [byte[0] intValue] & 0xffff;
+			const int value = [byte[1] intValue];
+
+			if(ram_[address] != value) {
+				NSLog(@"Value at address %04x should be %02x; is %02x", address, value, ram_[address]);
+				failed = true;
+			}
+		}
+
+		// Check ports.
+		if(!ports_matched()) {
+			NSLog(@"Mismatch in port activity");
+			failed = true;
+		}
+
+		return !failed;
+	}
+
+	bool compare_bus_states([[maybe_unused]] NSArray<NSArray *> *states) {
+/*		auto capture = bus_records_.begin() + 1;
+
+		int cycle = 0;
+		for(NSArray *state in states) {
+			// Extract proper bus state.
+			const std::optional<uint16_t> address =
+				[state[0] isKindOfClass:[NSNumber class]] ? std::optional<uint16_t>([state[0] intValue]) : std::nullopt;
+			const std::optional<uint8_t> data =
+				[state[1] isKindOfClass:[NSNumber class]] ? std::optional<uint8_t>([state[1] intValue]) : std::nullopt;
+
+			NSString *const controls = state[2];
+			const bool read = [controls characterAtIndex:0] != '-';
+			const bool write = [controls characterAtIndex:1] != '-';
+			const bool m1 = [controls characterAtIndex:2] != '-';
+			const bool ioReq = [controls characterAtIndex:2] != '-';
+
+			// Compare to captured state.
+			bool failed = false;
+			if(address != capture->address) {
+				NSLog(@"Address mismatch after %d cycles", cycle);
+				failed = true;
+			}
+			if(data != capture->data) {
+				NSLog(@"Data mismatch after %d cycles", cycle);
+				failed = true;
+			}
+
+			using Line = CPU::Z80::PartialMachineCycle::Line;
+			if(read != bool(capture->lines & Line::RD)) {
+				NSLog(@"Read line mismatch after %d cycles", cycle);
+				failed = true;
+			}
+			if(write != bool(capture->lines & Line::WR)) {
+				NSLog(@"Write line mismatch after %d cycles", cycle);
+				failed = true;
+			}
+			if(m1 != bool(capture->lines & Line::M1)) {
+				NSLog(@"M1 line mismatch after %d cycles", cycle);
+				failed = true;
+			}
+			if(ioReq != bool(capture->lines & Line::IOREQ)) {
+				NSLog(@"IOREQ line mismatch after %d cycles", cycle);
+				failed = true;
+			}
+
+			if(failed) {
+				return false;
+			}
+
+			// Advance.
+			capture += 2;
+			++cycle;
+		}*/
+
+		return true;
+	}
+
+	void run_for(int cycles) {
+		z80_.run_for(HalfCycles(Cycles(cycles)));
+		XCTAssertEqual(bus_records_.size(), cycles * 2);
+	}
+
+	struct BusRecord {
+		std::optional<uint16_t> address = 0xffff;
+		std::optional<uint8_t> data = 0xff;
+		uint8_t lines = 0xff;
+
+		BusRecord(std::optional<uint16_t> address, std::optional<uint8_t> data, uint8_t lines) :
+			address(address), data(data), lines(lines) {}
+	};
+
+	HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
+
+		//
+		// Do the actual action.
+		//
+		switch(cycle.operation) {
+			default: break;
+
+			case CPU::Z80::PartialMachineCycle::Read:
+			case CPU::Z80::PartialMachineCycle::ReadOpcode:
+				*cycle.value = ram_[*cycle.address];
+			break;
+
+			case CPU::Z80::PartialMachineCycle::Write:
+				ram_[*cycle.address] = *cycle.value;
+			break;
+
+			case CPU::Z80::PartialMachineCycle::Input:
+				if(next_port_ != expected_port_accesses_.end() && next_port_->is_read && next_port_->address == *cycle.address) {
+					*cycle.value = next_port_->value;
+					++next_port_;
+				} else {
+					ports_matched_ = false;
+					*cycle.value = 0xff;
+				}
+			break;
+
+			case CPU::Z80::PartialMachineCycle::Output:
+				if(next_port_ != expected_port_accesses_.end() && !next_port_->is_read && next_port_->address == *cycle.address) {
+					ports_matched_ &= *cycle.value == next_port_->value;
+					++next_port_;
+				} else {
+					ports_matched_ = false;
+				}
+			break;
+		}
+
+		//
+		// Capture bus activity.
+		//
+		const auto data = cycle.value ? std::optional<uint8_t>(*cycle.value) : std::nullopt;
+		const auto address = cycle.address ? std::optional<uint16_t>(*cycle.address) : std::nullopt;
+		const auto bus = cycle.bus_state<CPU::Z80::PartialMachineCycle::SampleType::Instant>();
+		for(int i = 0; i < cycle.length.as<int>(); i++) {
+			bus_records_.emplace_back(address, data, bus[i]);
+		}
+
+		return HalfCycles(0);
+	}
+
+	const std::vector<BusRecord> &bus_records() const {
+		return bus_records_;
+	}
+
+	bool ports_matched() const {
+		return ports_matched_ && next_port_ == expected_port_accesses_.end();
+	}
+
+	private:
+		CPU::Z80::Processor<CapturingZ80, false, false> z80_;
+		uint8_t ram_[65536];
+
+		struct PortAccess {
+			const uint16_t address = 0;
+			const uint8_t value = 0;
+			const bool is_read = false;
+
+			PortAccess(uint16_t a, uint8_t v, bool r) : address(a), value(v), is_read(r) {}
+		};
+		std::vector<PortAccess> expected_port_accesses_;
+		std::vector<PortAccess>::iterator next_port_;
+		bool ports_matched_ = true;
+
+		std::vector<BusRecord> bus_records_;
+};
+
+}
+
+@interface Z80JSMooTests : XCTestCase
+@end
+
+@implementation Z80JSMooTests
+
+- (BOOL)applyTest:(NSDictionary *)test {
+	// Log something.
+//	NSLog(@"Test %@", test[@"name"]);
+
+	// Seed Z80 and run to conclusion.
+	auto z80 = std::make_unique<CapturingZ80>(test[@"initial"], test[@"ports"]);
+	z80->run_for(int([test[@"cycles"] count]));
+//	z80->run_for(15);
+
+	// Check register and RAM state.
+	return z80->compare_state(test[@"final"]) && z80->compare_bus_states(test[@"cycles"]);
+}
+
+- (BOOL)applyTests:(NSString *)path {
+	NSArray<NSDictionary *> *const tests =
+		[NSJSONSerialization JSONObjectWithData:
+			[NSData dataWithContentsOfFile:path]
+		options:0
+		error:nil];
+
+	XCTAssertNotNil(tests);
+
+	BOOL allSucceeded = YES;
+	for(NSDictionary *test in tests) {
+		allSucceeded &= [self applyTest:test];
+
+		if(!allSucceeded) {
+			NSLog(@"Failed at %@", test[@"name"]);
+			return NO;
+		}
+	}
+
+	// TODO: switch to the below, or some approximation thereof.
+	// Current issue: Z80 construction assumes something heading towards 500kb
+	// of stack is available, and dispatch_apply seems to create an environment
+	// much tighter than that.
+
+//	__block BOOL allSucceeded = YES;
+//
+//	const size_t pageSize = 10;
+//	const auto stepsPerBlock = size_t([tests count] / pageSize);
+//	dispatch_apply(pageSize, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(size_t index) {
+//		const size_t start = index * stepsPerBlock;
+//		for(size_t c = start; c < start + stepsPerBlock; c++) {
+//			assert(c < tests.count);
+//			NSLog(@"%d begins %d", int(index), int(c));
+//
+//			allSucceeded &= [self applyTest:tests[c]];
+//
+//			if(!allSucceeded) {
+//				NSLog(@"Failed at %@", tests[c][@"name"]);
+//				return;
+//			}
+//		}
+//    });
+
+	return allSucceeded;
+}
+
+- (void)testAll {
+	// Get a list of everything in the 'TestPath' directory.
+	NSError *error;
+	NSString *const testPath = @(TestPath);
+	NSArray<NSString *> *const sources =
+		[[NSFileManager defaultManager] contentsOfDirectoryAtPath:testPath error:&error];
+
+	// Optional: a permit list; leave empty to allow all tests.
+	NSSet<NSString *> *permitList = [NSSet setWithArray:@[
+//		@"cb 46.json",
+//		@"cb 4e.json",
+//		@"cb 56.json",
+//		@"cb 5e.json",
+//		@"cb 66.json",
+//		@"cb 6e.json",
+//		@"cb 76.json",
+//		@"cb 7e.json",
+		@"ed a2.json",
+//		@"ed b2.json"
+	]];
+
+	// Treat lack of a local copy of these tests as a non-failing condition.
+	if(error || ![sources count]) {
+		NSLog(@"No tests found at %s; not testing, not failing", TestPath);
+		return;
+	}
+
+	// Apply tests one by one.
+	NSMutableArray *failures = [[NSMutableArray alloc] init];
+	for(NSString *source in sources) {
+		if(![[source pathExtension] isEqualToString:@"json"]) {
+			NSLog(@"Skipping %@", source);
+			continue;
+		}
+
+		// Skip if: (i) there is a permit list; and (ii) this file isn't on it.
+		if([permitList count] && ![permitList containsObject:source]) {
+			continue;
+		}
+
+		NSLog(@"Testing %@", source);
+		if(![self applyTests:[testPath stringByAppendingPathComponent:source]]) {
+			NSLog(@"Failed");
+			[failures addObject:source];
+		}
+	}
+
+	[failures sortUsingComparator:^NSComparisonResult(NSString *obj1, NSString *obj2) {
+		if([obj1 length] < [obj2 length]) {
+			return NSOrderedAscending;
+		}
+		if([obj2 length] < [obj1 length]) {
+			return NSOrderedDescending;
+		}
+
+		return [obj1 compare:obj2];
+	}];
+	NSLog(@"Files with failures were: %@", failures);
+
+	XCTAssertEqual([failures count], 0);
+}
+@end

Processors/Z80/Implementation/Z80Base.cpp

@@ -62,6 +62,7 @@ uint16_t ProcessorBase::value_of(Register r) const {
 		case Register::IM:						return uint16_t(interrupt_mode_);
 
 		case Register::MemPtr:					return memptr_.full;
+		case Register::DidChangeFlags:			return flag_adjustment_history_ & 1;
 
 		default: return 0;
 	}
@@ -115,6 +116,7 @@ void ProcessorBase::set_value_of(Register r, uint16_t value) {
 		case Register::IM:				interrupt_mode_ = value % 3;			break;
 
 		case Register::MemPtr:			memptr_.full = value;						break;
+		case Register::DidChangeFlags:	flag_adjustment_history_ = value ? 1 : 0;	break;
 
 		default: break;
 	}

Processors/Z80/Implementation/Z80Implementation.hpp

@@ -877,6 +877,9 @@ template <	class T,
 				case MicroOp::SetInstructionPage:
 					current_instruction_page_ = static_cast<InstructionPage *>(operation->source);
 					scheduled_program_counter_ = current_instruction_page_->fetch_decode_execute_data;
+
+					// Undo spurious history update.
+					flag_adjustment_history_ >>= 1;
 				break;
 
 				case MicroOp::CalculateIndexAddress:
@@ -928,7 +931,7 @@ template <	class T,
 template <	class T,
 			bool uses_bus_request,
 			bool uses_wait_line> void Processor <T, uses_bus_request, uses_wait_line>
-				::assemble_page(InstructionPage &target, InstructionTable &table, bool add_offsets) {
+				::assemble_page(InstructionPage &target, const InstructionTable &table, bool add_offsets) {
 	std::size_t number_of_micro_ops = 0;
 	std::size_t lengths[256];
 

Processors/Z80/Implementation/Z80Storage.hpp

@@ -224,7 +224,7 @@ class ProcessorStorage {
 		}
 
 		typedef MicroOp InstructionTable[256][30];
-		virtual void assemble_page(InstructionPage &target, InstructionTable &table, bool add_offsets) = 0;
+		virtual void assemble_page(InstructionPage &target, const InstructionTable &table, bool add_offsets) = 0;
 		virtual void copy_program(const MicroOp *source, std::vector<MicroOp> &destination) = 0;
 
 		void assemble_fetch_decode_execute(InstructionPage &target, int length);

Processors/Z80/Z80.hpp

@@ -10,8 +10,8 @@
 
 #include <algorithm>
 #include <cassert>
-#include <vector>
 #include <cstdint>
+#include <vector>
 
 #include "../../Numeric/RegisterSizes.hpp"
 #include "../../ClockReceiver/ClockReceiver.hpp"
@@ -42,7 +42,12 @@ enum class Register {
 
 	IFF1,	IFF2,	IM,
 
-	MemPtr
+	MemPtr,
+
+	/// Obscure, and related to status bits 3 & 5 upon an SCF or CCF; this
+	/// is a single bit indicating whether an immediately-following [S/C]CF
+	/// can only set bits 3 & 5 or may also reset them.
+	DidChangeFlags,
 };
 
 /*
@@ -151,19 +156,27 @@ struct PartialMachineCycle {
 		return operation <= Operation::Write;
 	}
 
-	enum Line {
+	using LineStateT = uint16_t;
-		CLK = 1 << 0,
+	struct Line {
+		static constexpr LineStateT CLK = 1 << 0;
 
-		MREQ = 1 << 1,
+		static constexpr LineStateT MREQ = 1 << 1;
-		IOREQ = 1 << 2,
+		static constexpr LineStateT IOREQ = 1 << 2;
 
-		RD = 1 << 3,
+		static constexpr LineStateT RD = 1 << 3;
-		WR = 1 << 4,
+		static constexpr LineStateT WR = 1 << 4;
-		RFSH = 1 << 5,
+		static constexpr LineStateT RFSH = 1 << 5;
 
-		M1 = 1 << 6,
+		static constexpr LineStateT M1 = 1 << 6;
 
-		BUSACK = 1 << 7,
+		static constexpr LineStateT BUSACK = 1 << 7;
+
+		static constexpr LineStateT DataActive = 1 << 8;
+		static constexpr LineStateT AddressActive = 1 << 9;
+	};
+
+	enum class SampleType {
+		Instant, Period
 	};
 
 	/// @returns A C-style array of the bus state at the beginning of each half cycle in this
@@ -171,7 +184,37 @@ struct PartialMachineCycle {
 	/// bit set means line active, bit clear means line inactive. For the CLK line set means high.
 	///
 	/// @discussion This discrete sampling is prone to aliasing errors. Beware.
-	const uint8_t *bus_state() const {
+	///
+	///	@c sample_type indicates whether to describe bus activity:
+	/// 	(i)	as a series of instantaneous samples indicating levels at the
+	/// 		immediate start of the time period; or
+	/// 	(ii)	as windowed samples, indicating active if the signal is active
+	/// 		at any time during this time period.
+	///
+	template <SampleType sample_type> const LineStateT *bus_state() const {
+		struct BusStateDecomposer {
+			static constexpr LineStateT state(const char *source) {
+				LineStateT result = 0;
+				while(*source) {
+					switch(*source) {
+						default: 									break;
+						case 'C':	result |= Line::CLK;			break;
+						case 'M':	result |= Line::MREQ;			break;
+						case 'I':	result |= Line::IOREQ;			break;
+						case 'R':	result |= Line::RD;				break;
+						case 'W':	result |= Line::WR;				break;
+						case 'F':	result |= Line::RFSH;			break;
+						case '1':	result |= Line::M1;				break;
+						case 'K':	result |= Line::BUSACK;			break;
+						case 'D':	result |= Line::DataActive;		break;
+						case 'A':	result |= Line::AddressActive;	break;
+					}
+					++source;
+				}
+				return result;
+			}
+		};
+
 		switch(operation) {
 
 			//
@@ -179,25 +222,30 @@ struct PartialMachineCycle {
 			//
 
 			case Operation::ReadOpcodeStart: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT period_states[] = {
-					Line::CLK |	Line::M1,
+					BusStateDecomposer::state("C 1__ A"),
-								Line::M1 |	Line::MREQ |	Line::RD,
+					BusStateDecomposer::state("_ 1MR A"),
-					Line::CLK |	Line::M1 |	Line::MREQ |	Line::RD,
+					BusStateDecomposer::state("C 1MR A"),
 				};
-				return states;
+				static constexpr LineStateT instant_states[] = {
+					BusStateDecomposer::state("C ___ _"),
+					BusStateDecomposer::state("_ 1M_ A"),
+					BusStateDecomposer::state("C 1MR A"),
+				};
+				return sample_type == SampleType::Period ? period_states : instant_states;
 			}
 
 			case Operation::ReadOpcode:
 			case Operation::ReadOpcodeWait: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
-								Line::M1 |	Line::MREQ |	Line::RD,
+					BusStateDecomposer::state("_ 1MR A"),
-					Line::CLK |	Line::M1 |	Line::MREQ |	Line::RD,
+					BusStateDecomposer::state("C 1MR A"),
 				};
 				return states;
 			}
 
 			case Operation::Refresh: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 					Line::CLK |	Line::RFSH |	Line::MREQ,
 								Line::RFSH,
 					Line::CLK |	Line::RFSH |	Line::MREQ,
@@ -215,7 +263,7 @@ struct PartialMachineCycle {
 			//
 
 			case Operation::ReadStart: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 					Line::CLK,
 								Line::RD |	Line::MREQ,
 					Line::CLK |	Line::RD |	Line::MREQ,
@@ -224,7 +272,7 @@ struct PartialMachineCycle {
 			}
 
 			case Operation::ReadWait: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 								Line::MREQ |	Line::RD,
 					Line::CLK |	Line::MREQ |	Line::RD,
 								Line::MREQ |	Line::RD,
@@ -236,7 +284,7 @@ struct PartialMachineCycle {
 			}
 
 			case Operation::Read: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 								Line::MREQ |	Line::RD,
 					Line::CLK |	Line::MREQ |	Line::RD,
 								0,
@@ -249,7 +297,7 @@ struct PartialMachineCycle {
 			//
 
 			case Operation::WriteStart: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 					Line::CLK,
 								Line::MREQ,
 					Line::CLK |	Line::MREQ,
@@ -258,7 +306,7 @@ struct PartialMachineCycle {
 			}
 
 			case Operation::WriteWait: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 								Line::MREQ,
 					Line::CLK |	Line::MREQ,
 								Line::MREQ,
@@ -270,7 +318,7 @@ struct PartialMachineCycle {
 			}
 
 			case Operation::Write: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 								Line::MREQ |	Line::WR,
 					Line::CLK |	Line::MREQ |	Line::WR,
 								0,
@@ -283,7 +331,7 @@ struct PartialMachineCycle {
 			//
 
 			case Operation::InputStart: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 					Line::CLK,
 								0,
 					Line::CLK |	Line::IOREQ |	Line::RD,
@@ -292,7 +340,7 @@ struct PartialMachineCycle {
 			}
 
 			case Operation::InputWait: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 								Line::IOREQ |	Line::RD,
 					Line::CLK |	Line::IOREQ |	Line::RD,
 				};
@@ -300,7 +348,7 @@ struct PartialMachineCycle {
 			}
 
 			case Operation::Input: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 								Line::IOREQ |	Line::RD,
 					Line::CLK |	Line::IOREQ |	Line::RD,
 								0,
@@ -313,7 +361,7 @@ struct PartialMachineCycle {
 			//
 
 			case Operation::OutputStart: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 					Line::CLK,
 								0,
 					Line::CLK |	Line::IOREQ |	Line::WR,
@@ -322,7 +370,7 @@ struct PartialMachineCycle {
 			}
 
 			case Operation::OutputWait: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 								Line::IOREQ |	Line::WR,
 					Line::CLK |	Line::IOREQ |	Line::WR,
 				};
@@ -330,7 +378,7 @@ struct PartialMachineCycle {
 			}
 
 			case Operation::Output: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 								Line::IOREQ |	Line::WR,
 					Line::CLK |	Line::IOREQ |	Line::WR,
 								0,
@@ -347,7 +395,7 @@ struct PartialMachineCycle {
 			//
 
 			case Operation::BusAcknowledge: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 					Line::CLK |	Line::BUSACK,
 								Line::BUSACK,
 				};
@@ -359,7 +407,7 @@ struct PartialMachineCycle {
 			//
 
 			case Operation::Internal: {
-				static constexpr uint8_t states[] = {
+				static constexpr LineStateT states[] = {
 					Line::CLK, 0,
 					Line::CLK, 0,
 					Line::CLK, 0,
@@ -530,7 +578,7 @@ template <class T, bool uses_bus_request, bool uses_wait_line> class Processor:
 	private:
 		T &bus_handler_;
 
-		void assemble_page(InstructionPage &target, InstructionTable &table, bool add_offsets);
+		void assemble_page(InstructionPage &target, const InstructionTable &table, bool add_offsets);
 		void copy_program(const MicroOp *source, std::vector<MicroOp> &destination);
 };